I sometimes hear that European observers were present to some extent during the Civil War to see what was going on and "take notes" so to speak. And that they were eager to do so because the Civil War included a lot of new technology that hadn't been applied to European warfare on a large scale (telegraphs, railroads, and others).
Is there any truth to all of this?
There's always more to add, but u/vonadler wrote about this in a previous thread